Comparison of lignocellulose composition in four major species of Miscanthus
Miscanthus is a perennial grass rich in lignocellulose that has attracted interest as a non-food crop for renewable bioenergy with major environmental and economic benefits for China. The lignocellulose composition of whole stems of four major species of Miscanthus was assessed. The average values of total moisture content (TMC) (61.90%) and hemicelluloses (34.86%) were the highest while cellulose (32.71%) and acid detergent lignin (ADL) (8.90%) were the lowest in Miscanthus floridulus. On the contrary, the contents of cellulose (42.11%) and ADL (13.64%) were the highest and total ash (TA) (2.89%) was the lowest in Miscanthus lutarioriparius. The Shannon–Weaver diversity indices of components for the four species showed that hemicellulose content (H’= 2.00±0.11) was the most variable trait followed by cellulose (H’= 1.84±0.07), then ADL (H’= 1.84±0.07). The variational range of each component was relatively higher in Miscanthus sacchariflorus. In M. lutarioriparius, the diversity indices of each component were moderate. The diversity of cellulose was the highest and hemicellulose, ADL, TA and TMC were low in Miscanthus sinensis. By correlation analysis, neutral detergent fiber (NDF) significantly and positively correlated with ADF, cellulose and ADL at P<0.01 as well as the relationship of cellulose and ADL in the four species. Hemicellulose showed significant (P<0.01) but negative correlation with cellulose and ADL in M. floridulus, M. lutarioriparius and M. sacchariflorus. By principal component analysis (PCA), the components ADF and cellulose were the PC1 that were considered the foremost for the evaluation and selection of resource in the four species. The conclusions show that lignocellulose composition contents of Miscanthus culms were different. M. floridulus was more fit to ethanol fermentation. Though the components contents in M. sinensis and M. sacchariflorus were moderate, the range of choice was large. It provided a possible means to screen the appropriate materials according to different utilization. M. lutarioriparius had more superiorities relatively. So the four species of Miscanthus were appropriate for extension as excellent herbaceous energy plants, though, reasonable species choice should be employed according to the conversion approach and the growth characteristics, productivity levels and biomass quality characteristics of these tall grasses.
Keywords: Miscanthus, bioenergy, lignocellulose compositions, detergent fiber, diversity analysis, PCA